Why Are Men’s Sperm Rates Falling?

Men’s sperm production is decreasing rapidly and the scientific community is struggling to find an explanation, writes Dr Phil Hammond

Up to a fifth of young men have a low sperm count, defined as fewer than 20 million sperm per millilitre of semen. Quite why you need so many sperm to fertilize one egg remains a mystery, but a low sperm count or poor sperm quality is the main cause of infertility in about 20pc of couples with fertility problems in the UK, and is an ‘additional factor’ in a further 25pc of cases. So what’s going on? The much publicised decline of man has been on the cards since 1992, when seminal Danish research found that the number of sperm in each millilitre of semen has halved since the World War Two, while abnormal sperm (double-headers, big-headers, double-tailers and slow-coaches) is on the rise.

This was replicated in a French study, based on sperm samples from 26,600 healthy men, that found a substantial decline in average sperm counts between 1989 and 2005, from 73.6 million to 49.9 million per millilitre. It should be mentioned that Italian researches have found their sperm numbers going up in the last decade – but then Italy loves to be different. Nobody’s quite sure what’s behind the general drop-off. It could be diet, environment, or girl power. The trouble with science is not just that there often isn’t a single answer. And modern ethics dictates that you can’t just lock, say, a few medical students in a chamber full of insecticide and see what happens to their puberty. Instead, you have to wait for an environmental accident that affects humans.

There does at least appear to be some circumstantial evidence to support what’s known as ‘the oestrogen hypothesis’. This holds that some of the 5,000 or so chemicals that inhabit our food, fertilizers and industrial cleaners are not dissimilar to the female sex hormone oestrogen – only they hang round a lot longer and at levels up to a thousand times higher than normal. This may have adverse effects on oestrogen-sensitive areas of the body (the reproductive tracts, breast, womb and possibly the developing foetus), which may possibly contribute to infertility and testicular cancer in men, breast and womb cancer in women and fetal abnormalities. The theory originates from 1980, when thousands of gallons of DDT were accidentally spilt into a wildlife haven, Lake Apopka, near Orlando, Florida.

In the following four years, the death rate for alligator eggs rose from 57 to 96pc and the males became sterile with shrunken, useless penises and very low testosterone levels. Was DDT to blame? We might never know. Back home on the British south coast, female dogwhelks have been developing pseudopenises, possibly due to oestrogenic chemicals used for boat painting, and male fish foolish enough to swim in sewerage outlets have been losing their tackle. From such environmental cock-ups are theories formed, and the oestrogen hypothesis is supported by a famous medical mistake. DES, a synthetic oestrogen, was given to millions of women between 1945 and 1971 to prevent miscarriage, but many of the children born subsequently had genital abnormalities, including decreased sperm quality and undescended testicles.

loading...

Although DES is no longer prescribed, the theory goes that the increase in consumption of hormone-rich dairy produce, the use of the contraceptive pill and other steroid drugs, and oestrogenic environmental pollutants such as DDT, PCBs, plastic wrapping and exhaust fumes are all conspiring to wipe out our reproductive ability. Certainly it has given environmentalists plenty to shout about, with some calling for an immediate ban on all things oestrogenic and predicting the destruction of the human race by Clingfilm. Most of the population quietly get on with their lives without paying too much heed to unproved possibilities, but others are more anxious. As one would-be father asked me: “We’re trying for a baby this month. Should we be drinking tap water?”.

Well, it’s a damn site better for you than drinking untreated sewage. Research from Brunel University found very few oestrogenic chemicals (except at effluent outlets) in British tap water, and concluded that any oestrogenic contaminants that might possibly harm us are likely to come from food. As there are 5,000 food chemicals to test and science requires that only one be tested at a time, it’ll be a little while yet before we know the true state of play. As to why the dip has occurred, it all depends on which planet you inhabit. Is it God’s way of punishing human greed or Mother Earth’s answer to environmental destruction? Is it a Darwinian response to over-population (sperm were up after WW2 because we needed to replace our young men, but that need has now passed).

Is “stress” the trigger? Or perhaps the pervading feeling of male helplessness as women take over the planet has stunted our development to such an extent that we just can’t be bothered to play ball. There are lots of other possible causes of low sperm count. like steroid abuse or undescended testicles, and equally lots that can be done to help. For more information. In the meantime, if you do want to give whatever sperm you have every chance of success, follow the top tips below:

How to keep your sperm alive

Try not to overdose on your partner’s contraceptive pills

Air your genitals at every socially acceptable opportunity

Piping hot baths are out

Don’t go swimming in untreated sewage

Avoid radiation, industrial cleaners and children with mumps if you haven’t had it

No tight G strings – Let ‘em hang

Cut down on the things you associate with pubs (smoking, excessive alcohol, unprotected sex with strangers)